1. Field of the Invention
The invention relates to a striker drive assembly for a motor vehicle door lock or the like with a drive that, preferably, has a drive motor with a downstream gearing. In particular, the invention relates to such a striker drive assembly which is provided with a linearly movable striker carrier which is positioned to move in a housing to which the drive is joined and which can be motor-driven by means of a drive element, preferably by means of a cam, and with a striker which is attached to the striker carrier.
2. Description of Related Art
Motor vehicle door locks or the like which are provided with a motor-driven closing aid to make operation easier have been known for some time. Motorized closing aids in locks for tailgates and rear doors are very common, but in the meantime, motorized closing aids for motor vehicle side doors are also becoming more popular.
In a first type of motor vehicle door lock or the like, the motorized closing aid is assigned to the latch, while the striker on the opposite part of the car body, for example, the B pillar or C pillar, is stationary and is used as an abutment.
The aforementioned first type of motorized closing aid is advantageous, but also has construction and operating problems. To solve these problems, a second type of motor vehicle door lock or the like has become known in which the motorized closing aid is assigned to the striker instead of to the latch. This yields a striker drive assembly on the corresponding part of the car body, for example, on the B pillar or the C pillar. A striker drive assembly on a stationary part of the car body, for example, the B pillar, has various advantages. The actuating mechanism and central interlock of the motor vehicle door lock or the like are independent of the drive means of the closing aid. The drive means of the closing aid is stationary on the car body, and is not exposed to high accelerations when the motor vehicle door is slammed shut. Structurally bypassing the drive motor of the drive means, which is necessary for safety reasons for purposes of emergency opening, is produced by itself since the actuating mechanism remains effective for manual actuation with respect to the latch, regardless of the position the striker moved by the drive means.
A striker drive assembly of the type to which the present invention is directed having a linearly movable striker carrier is known from U.S. Pat. Nos. 4,707,007 and 4,982,984. This striker drive assembly can be used in side doors, rear doors, tailgates, trunk decks, hoods, or the like.
In the known striker drive assembly, first of all, the striker is detachably and interchangeably attached to the striker carrier. It is specifically screwed on the striker carrier there. Thus, the striker drive assembly can be universally used since, for each type of motor vehicle, the suitable desired striker can be attached to the striker carrier, for example, a wedge-shaped striker, a striker made as a closing clip, a striker made as a bolt, etc.
In the known striker drive assembly, the striker carrier is positioned to move in a housing to which the drive means is permanently joined. The drive means, here, comprises an electrical drive motor and a step-down gear made as toothed gearing. As an alternative, other drive motors (hydraulic, pneumatic), other gearing (worm gear pair) and direct drives (hydraulic cylinder with rack) etc. are mentioned. The assembly consisting of the housing and drive means itself is then provided with attachment means for attachment to the desired car body part. These attachment means, in the prior art, are mounting screws, i.e., the assembly is attached to the car body, as were the earlier pure strikers, without drive assemblies.
In the known striker drive assembly, the striker carrier can be driven via a cam which fits into a receptacle on the striker carrier. On the edge of the receptacle, in the striker carrier, a force transmission surface is formed against which the cam rests with low friction to transmit force. The size of the receptacle is tailored to the size of the cam; thus, the striker carrier follows each movement of the cam. In the above explained known striker drive assembly with a linearly movable striker carrier to which the invention is directed, vigorous slamming of the motor vehicle door, at the same time, loads the cam because the striker cannot yield. In the open position (preclosing position), the striker is blocked if the drive means should fail when the cam is in the open position (preclosing position). The motor vehicle door then only reaches the "precatch"; this is acceptable for a certain time in terms of safety engineering, but is uncomfortable.
Otherwise, the behavior of the striker drive assembly, aside from the linear movability of the striker carrier, should correspond as much as possible to the behavior of a striker screwed stationary onto the car body part without a drive means.